COLUMBUS model 90 Made in New Zealand in 1945. Part 1
Vložit
- čas přidán 7. 09. 2024
- In my last video I asked viewers which radio they would like me to work on next. This Columbus model 90 was by far the most requested.
Made in 1945 by the Radio Corporation of New Zealand this is a monster of a radio and unique in a number of ways.
So here it is.
I thought it would be a pretty straightforward restoration but the radio had other ideas.
Fortunately the amazing radio restoration community has come to the rescue once again.
Thanks to:
Vintage Radio Steve:
www.vintageradio.co.nz
UC84VF9fYxDwq77Rw8FUh60A
and
Ron Pond
Carl's Capacitors:
www.ebay.com.a...
#radio
#tube
#valve
#Columbus
#repair
#restoration
#Radio Corporation of New Zealand
That is a beast Don, it would have been expensive set to buy. Good that Ron was able to supply a new transformer so quickly, hopefully mounting it 90 degrees from original doesn't create any problems. Steve is a good bloke, I have had quite a bit of interaction with him, he has been a bit quiet lately YT wise. The field coil resistance does sound a bit low, I wonder if that caused the TX to overheat? I will be happy to rewind it if that is the case, Bermuda sounds nice this time of year 😉😄
Bermuda lol. I was thinking more of the Brisbane River. They do a nice sunset cruise, I believe (BYO sunset).😜
I just pulled the speaker out and having a look at it. I'll let you know how it goes. Steve tells me it should be 1500 ohms but I may have been mistakenly looking across the OPT primary.
I was wondering about mounting the transformer sideways. Hopefully it will be ok. I can turn it 90 degrees but I would have to move the filter caps so I won't do it unless I have to.
Cheers
Haha... Brisbane River indeed 😅😅😅
Hi David. Bad news about the field coil - it's open. I must have been looking at the output tranny primary - it's about 450...
I undid the wrappings on the coil and it looks clean & unburnt but I couldn't see the break, I wasn't going to try unwinding any of it - I'd prefer to leave that to someone who knows what they're doing and has the equipment. So, if the offer is still open I'll post it off on Monday. I measured the wire at 0.18 mm but I don't trust my garage sale micrometer so you had better check. I don't know if it would be possible to re-wind the original wire back on if the break was near the outside. The wire looked good on the outer layer (apart from some tape residue)
I know it's going to cost a bit but I'm already in pretty deep with this radio and I would like to see it working again with the original speaker.
Cheers
@@Donno308You know, if you’re going to send the field coil, it sure would be nice to have the original transformer back in there… just sayin’ 😉 David does have that sweet winding machine, and I wouldn’t mind if he put out a whole “collaboration” video! 😎
@@Donno308 I sent you a PM Don.
Interesting repair so far 👍
Those roosters though 🤣
Nice start, Don (and thanks for making me blush - there are plenty of things I don't know about Kiwi radios...). Replacing those transformers can be a frustrating task, due to the way the wiring is packed in. They were never wax-impregnated when Radio Corp made them, and I think one of the failure modes is the windings loosening up, then humming and vibrating, leading to shorts and then eventual failure.
And it sounds like the speaker field coil has shorted - it should be 1500 ohms. Possibly taken out by the failing power TX. They can be re-wound, although I don't remember the wire gauge offhand. Something fine. Those 10" Radio Corp speakers sound fabulous, so it is definitely worth fixing. I'll see if I have a spare field coil here - although I don't think so. Not intact, anyway.
Oh, and those soldered-in upright can caps will be tropicalised 0.1uF paper caps - they can be easily desoldered from the holder and then replaced with something that isn't oily and sticky. The nice thing with them (and possibly why they were done that way) is that they provide a solid tie point in the chassis. And I suspect that Solar cap is a replacement - they either made their own caps (which will be labelled Radio Corp NZ) or they typically used Ducon and Hunts in that era (although in the post-war shortages, they (like everyone) used what they could get). Their own caps were being used in military contracts through the war as well, and can be found in military ZC1 transceivers, among other sets.
And that set should have 2 dial lights, someone has removed one - and yes, there is a very low resistance often used in-line with the dial lights, or a tap on the 6.3V winding - reducing the dial light voltage by about 10% vastly improved lamp life.
I'm very much looking forward to part 2 🙂
Cheers, Steve
Thanks Steve. I took the speaker out and checked again. I was mistaken about the 500 ohms - it's completely open. It doesn't look burnt or anything and the wire doesn't look cooked. I unwrapped it but couldn't find the break. I'm thinking of sending it off to David Tipton for a rewind if I can't get a replacement.
I seem to have a mix of caps - some look like Ducon and I think there's another Solar. I was amazed that that one checked ok. I'm thinking of fitting new .1uF caps inside those cans. They're kind of a unique feature of this chassis and despite the substitute transformer I would like to keep it as original as I can.
Part 2 should be along in maybe 3 weeks.
Cheers
The Can below the magic eye is an inductor part of the negative feedback tone control circuit. The field coil is around 1500 ohms. Beware doing an IF alignment, these Radios had a wide IF bandwidth and the description of the lineup is in the manual. These Radios had Jansen designed electrodynamic speakers and together with the wide IF and negative feedback tone control, they sound fantastic for AM.
Thanks. Yes I worked out the choke in the tone control circuit. Thanks for the tip re the IF. I'll follow the instructions closely.
Thanx so much for doing this Don - I wish I had one to play with/fix. Re. the transformer, if the laminations are the same size as the original, it should be possible to use the bells off the old one (after cleaning the soot out first) to make the Philips one look a bit more original. Also, that bare wire trapped between the bell & the laminations would likely connect to an electrostatic shield between the primary & first secondary. It would naturally be earthed.
Hi. Thanks for the info about the electrostatic shield. That sounds right. I'm no expert about transformers. Unfortunately the laminations on the replacement transformer are bigger than the original so swapping the bells over isn't an option.
Cheers
Looks like a nice start. I'm glad Steve came to the rescue. I just subscribed to his channel, but as it's past my bedtime, I'll be checking it out in the morning. Looking forward to the next installment......
Hi Chuck. Yes, Steve's been very helpful. At least I'm off to a start with this one. Not out of the woods yet though.
You certainly have a lively neighborhood, Don, with the roosters and motorbikes and all!😉
Lol yes. We live in the best part of town!
Sorry to read about the field coil Don-a collab with Dave beckons I think, as various Columbus radio parts crisscross Australia!
I can't imagine a HT short causing a failure of the transformer primary AND the field coil, so I'd be putting them down to isolated failures, but no doubt you'll check all that.
Great to see you back after your break.
Hey Roundy
Yes the field coil was a bummer. It's on its way to Dave Tipton (at the mercy of Australia Post) as I type.
What happened to this radio is a mystery. Could they be isolated failures?
My current theory is the primary windings started to short out increasing the secondary voltage as the effective turns ratio increased and this blew the field coil.
But its only a theory and the truth is I have no idea. It does look as if the radio was left switched on, smoking and shouldering for some time to cook the transformer like that.
Anyway whatever, I'm reasonably hopeful that the old girl will sing again
Really enjoyed this one and looking forward to seeing the next instalment. Thank you so much for your kindness in sharing
Glad you enjoyed it!
Good work, Don! Power transformer primary failures are relatively rare, in my experience. Usually it’s the HV (aka HT) secondary that goes. Glad you got a replacement. You’re on your way.
Funny to see a radio on your or David Tipton’s channel without an Aussie “stationized” dial. Just markings in kilohertz….what a concept! ;-)
Hi. I wonder if Australia is the only country that has stations marked on our radio dials. I haven't seen any others. Shortwave dials often have countries or even cities marked but I've never seen individual stations anywhere else.
Yes, on my way now the transformer is transforming. Not out of the woods yet though...
@@Donno308 Here in NZ we have a lot of radios with stations marked:)
Lookin really good from the USA Donnie Boy! Good thing you had some backup from Perth.😊
Hi Jim
You got that right!
Cheers
Excellent start Don. love the side kick to Dave Tipton I'm sure he would help you if you needed it. Come on on you viewers give a thumbs up it helps promote these selective channels we all love about vintage radio & amps.
Hi,
Yes Dave is always willing to help and he is helping me with another issue with this radio as you'll see in the next part. We have a great vintage radio / restoration community.
Cheers
I REALLY enjoy 😉 your radio videos 📹. I thought the "moo" sound was your desoldering iron or something 🤔. Your friend, Jeff.
Lol I'd worry if my soldering iron started mooing! Some idiot on what sounds like a scooter with no muffler, probably unlicensed. You can hear it off and on through the video.
It's that kinda neighbourhood.
AT THE 27:52 MARK, LIKE SHANGO 066 WOULD SAY **BAKED!!**
Nice work Don, so glad you also managed to find an original nob to replace the missing one. Good luck with part two, I'm sure you will concor this beast as it looks like a pretty good
Looking one aswell. Cheers.
Hi Dom. Yes I didn't think I's ever find one. I was looking at moulding one but I don't know how successful that would be. Unfortunately the radio has a few more problems but I'm confident it will sing again.
Great work. This was the radio equivalent of a heart transplant. Well done.
Glad you enjoyed it!
Hi Don, Nice to see you back. the electrolytics may be PCB filled. the fluid has a fresh odor and is somewhat sticky. the direction of the laminations probably should match the old transformer to reduce any hum that may be induced.
Rich
I once read that the electrolyte was ammonium borate solution. However, those other oozing caps may well be paper impregnated with PCB which is leaking.
Hi Rich, The stuff coming out of those caps seems oily but has no smell. Not sure what it is. Steve says they're "tropicalised" caps. In any case I'll replace them with Carl's Amber caps. I may put the replacement caps inside the cans just for appearance. David Tipton also mentioned the direction of the laminations. I'll turn it around if I have a problem but I would have to move the filter caps so I'm hoping it'll be alright.
Cheers
! Good thing NZ is full of spare knobs
Looking good Don
❤😂🎉😊😊😊
Crispy.
Love the Roosters
FYI: The ship logo is the Santa Maria, Christopher Columbus's ship. The story goes that William Marks, a Russian émigré escaping the communist rule in the mid 1920's, wanted to go to America, but ended up in New Zealand (there is a chapter in my book on Radio Corp NZ on this). The brand name was a tribute to his long-held dream, although he later travelled there buying parts and hiring staff and was said to have told his family that he was glad that fate had sent him to New Zealand in the end. The brand was actually originally used for exports to Australia (10 years before this set was made) - but they ceased exports in 1937, around the same time they set up Columbus Radio Centres across New Zealand, to retail the brand here. Your set wouldn't have been retailed there. Do you know its history? I'd guess it was most likely dragged across by a Kiwi moving or retiring to a warmer climate...
Hi Steve. Thanks. That's an interesting story.
I bought the radio from a Kiwi couple who live nearby. He was a radio collector (not a restorer) and has some very nice Kiwi radios. They had just moved to a smaller house and were selling off excess radios etc. I also bought the Pacemaker off them.
WOW !! That primary looks horrible !!! I wonder what happened. Maybe there was a storm, lightning hit the mains and just destroyed the transformer ?
It's a mystery to me. Usually the secondary goes, not the primary. It must have been left switched on with the transformer burning for some time for that to happen.
34:00 Careful of the censors, Don! Hearing *fowl* language here! LOL😁
On the subject of New Zealand radio when i lived on the south coast at Nowra I use to pick up the signal of News Talk ZB Auckland like any other radio station it was mainly queensland and Victoria the strongest singnal would be now the defunked 4KQ that was under the *Classic Hits* Format 4BH has that format now since i have moved inland i can't pick up any long distance AM stations now as i cam close to over head power lines. 4KQ's Power output was 0,000 watts day/5,000 watts night.
@@Mediawatcher2023 0,000 w day? That's *ZERO SIGNAL!*
@@neilforbes416 10.000 watts i was meant to type.
i had one of those 300 in one experiment sets where you can buy them from Tandy and Dick Smiths Electronics
6:40 Tubes out of position? It was likely difficult to put them back in their respective sockets, considering that they were hard up against one wall of the cabinet.
@neilforbes416 once they are removed it be difficult to put back in
@@Mediawatcher2023 Bullshit! The chassis is removed from the cabinet, then all necessary work(replacing old electrolytic capacitors and other types of capacitors, plus out-of-tolerance resistors among other works, then Don will likely work on restoring the cabinet itself. Then all goes back together to reveal a restored NZ "Columbus" radio set.
@@neilforbes416 so you know the radio technology
@@Mediawatcher2023 I know a little, I tinkered with electronics as a teenager.
@@neilforbes416 i use to have one those 30 and 100 in one sets what you use to buy from Tandy and Dick Smith Electronics so much fun.
3:40 A New Zealand radio? *No chups!* LOL😁
It did come with chups but I already it thum.
@@Donno308 I hope you remimbered the tomato sauce! LOL😁
Take care, that electrolytic may retain hundreds of volts hours later. It happened to me once a long time ago. I dropped the chassis when it bit me!
I've had a similar experience. I won't do that again!
The forensic investigation of the old transformer shows how badly burnt up it got! The replacement one was checked for
output and voltage. She's good! Solar caps usually are crap by now! I don't have a China made tester like that as it's not made to check a capacitor's ability to handle much higher voltages than the tester puts out. Must replace all wax paper
and the electrolytic caps. Bury them in the bin. You're doing great Don and love the progress made so far. Steve from IL
in the USA
Hi Steve. Yes, I will replace all the paper caps anyway. This one has another Solar cap, a couple of Spragues and Ducons. Quite a mixture and, I think, all original. Not sure who made those ones that are leaking oil. They may also contain PCBs so I'll be changing those.
The little chinese capacitor tester is pretty good for what it is. One of these days I'll get myself a "proper" one that can test them up to their rated voltage. The value usually changes when a cap goes bad anyway but I only treat it as an indication.
I can only think that someone left this radio switched on, sizzling and smoking, for some time for the transformer to look like that. It's also taken out the speaker field coil. Luckily, David Tipton has offered to re-wind it for me. So meanwhile, it's on with the show!
Must be nearly Spring over your way. Lucky you! :-)
Cheers
Possibilities are: Primary shorted to ground, Secondary winding's shorted and Rectifier Tube shorted.
Hi Ted. I'm thinking maybe the primary shorted to ground. Secondaries seem ok and the rectifier tube seemed ok when I put power on it at the end of the video.
Vintage Radio Steve posted an interesting comment about the failure modes of these transformers.
@@Donno308 - Agree.
it's not shazzi. it's chassis not tchassis.
as in champagne or chamois
Now I'm confused. I thought that was what I said lol 😅
@@Donno308 no you said shazzi, that's why I commented. yanks are worse still they say tchassis, which annoys me Evan more than shazzi. think champagne or chamois, chammy.